MizuDroid is free for non-commercial use. Search for "MizuDroid" in the Google Play (Android Market) from your phone or visit the link below.
The MizuDroid Android softphone includes features specifically designed for business and enterprise users, including:
Google Play download
Android Softphone Forum
What is an Android softphone?
An android softphone is a software program for android devices allowing users to connect to a VoIP server and make calls to other VoIP users or to landline and mobile networks usually for lower prices than the native GSM calls.